Well logging apparatus



Nov. 29, 1955 s, E, BUCKLE-Y ETAL WELL LOGGING APPARATUS Filed April 50,i952 4 Sheets-Sheet l INVENTO. WHITMAN D. MOU/V AGEN Nov. 29, 1955 s, E.BUCKLEY l-:TAL 2,725,282

WELL LOGGING APPARATUS Filed April 30, 1952 4 Sheets-Sheet 2 Nov. 29,1955 s. E. BUCKLEY ETAL WELL LOGGING APPARATUS 4 Sheets-Sheet 5 FiledApril 30, 1952 WHITMAN D STg/YART E.

AGE 7'- Nov. 29, 1955 s. E. BUCKLEY ETAL 2,725,282

WELL LOGGING APPARATUS Filed April 3o, 1952 4 sheets-sheet 4 www -Illlllllllrlllllll 205 INVENTORS. wH/TMAN D. Mo UNCE STLRT E. BUCKLEY.

United States Patent WELL LOGGIN G APPARATUS Stuart E. Buckley andWhitman D. Mounce, Houston, Tex., assignors, by mesne assignments, tEsso Research and Engineering Company, Elizabeth, N. J., a corporationof Delaware Application April 30, 1952, Serial No. 285,222

Claims. (Cl. 23-253) The present invention is directed to apparatus forindicating the presence of petroliferous substances in an earthformation penetrated by a well bore. More particularly, the invention isdirected to apparatus for logging boreholes whereby the presence ofhydrocarbons and the like in the formation is indicated directly.

The invention may be briefly described as involving apparatus includinga body member adapted to be lowered and raised in a well borepenetrating an earth formation. The body member is provided with achamber or a reservoir which is adapted to contain a uid oxidizingagent. The body member has attached to it or carries at least anextension arm or an extensible member which is adapted to disrupt afilter cake on the wall of a well bore and to Contact a formationpenetrated by the well bore. The extension arm or extensible membercarries injection means which communicates with the reservoir forintroducing oxidizing agent into contact with the earth formation. Adetection means such as a thermocouple or a sound or pressure detectionmeans is carried by the body member and/or the means for lowering samein the well bore either interiorly or exteriorly to the body member oron the extension arm for detecting a reaction effect of the oxidizingagent with petroliferous substances or hydrocarbons in the formationpenetrated by the well bore.

In the apparatus of our invention it is possible to employ as oxidizingagents, oxidizing agents from a large number of materials which areknown to react with hydrocarbons. Among these known oxidizing agentsreactable with hydrocarbons are chlorine, perchloric acid, liquidoxygen, air, hydrogen peroxide, chlorosulfonic acid and the like. Itisalso possible to use the other perhalogen acids, such as perfluoricacid, per-iodic acid and perbromic acid. Other oxidizing agents whichare suitable in the practice of the present invention are a mixture ofnitrogen dioxide and aniline, potassium permanganate and chlorine, aquaregia, and the like. When chlorine is employed, it will be necessary toemploy a catalyst therefor. For example, red phosphorous in a nelydivided condition may be dispersed in the liqueed chlorine. Likewisewhen the perhalogen acids are employed, it may be desirable to use acatalyst to cause the oxidation reaction to proceed spontaneously at atemperature such as that encountered in a well bore. For example, it ispossible to employ perchloric acid having a strength in the range from70% to 84% HClO4 and temperatures down to as low as 40 C. by using acatalyst such as ceric ammonium nitrate. Other catalysts may be employedsuch as, for example, ammonium vanadate and osmium tetraoxide.

The reservoir in the apparatus of the present invention may be definedby the body member itself or there may be arranged in a cavity definedby the body member a deformable bag member which in turn is exposed tothe pressure suflicient to force the oxidizing agent from it. It isdesirable to incorporate in our apparatus means for imposing pressureand the like on the oxidizing agent ICC arranged in the reservoir. Thismay conveniently be done by employing an inert gas as a fluid piston orit may be desirable to employ a mechanical piston to urge the oxidizingagent from the reservoir and into contact with the formation.

The extension arm or extensible means may be carried by the body membersuch that at least an arm is depending or extending therefrom and whichmay be biased outwardly from the body member. For example, a pluralityof arms may be used and on the free end of each of said arms may bearranged a cutting or knife edge for disrupting the filter cake on thewall of a well bore, injection means communicating with the reservoir ordeformable bag member, and detection means carried by the free end ofthe extension arm to allow a determination of a reaction elect of thereaction caused by the oxidizing agent coming in contact withpetroliferous substance or hydrocarbons in the formation.

The extension arm or extensible means may suitably be a piston having ona free end thereof means for disrupting a lter cake on a wall of a wellbore. Such means may include a single or a plurality of knife edgeswhich are provided with ports communicating with a passageway in thepiston arm and, in turn, with a conduit connecting to the bag member.

The detection means may be a thermocouple or it may be a pressure orsound detection means. When a thermocouple is employed it may bedesirable to arrange the thermocouple on a free end of the extension armso that it may be adjacent'the reaction area. When the detection meansis a sound or pressure detection means the detection means may bearranged on the free end of the extension arm or it may be arranged inthe body member. It is contemplated, however, that the detection meansmay be carried by the conductor cable which is used to lower and raisethe body member. For example, a pressure detection means may be arrangedin a separate body member and connected to the cable employed to suspendthe body member or it may be made integral with the body member.

The present invention will be further described by reference to thedrawing in which Fig. 1 shows an embodiment for logging the well of awell bore;

Fig. 2 is a modification of the apparatus of Fig. l;

Fig. 3 is a fragmentary view showing a further embodiment of ourinvention in which different extension means are employed;

Fig. 4 is a modification of the apparatus of Fig. 3;

Fig. 5 illustrates a modification of our apparatus in which a pressurepickup is employed integral with the body member;

Fig. 6 is a sectional view of a suitable pressure pickup;

Fig. 7 is a view in section taken along line VII-VII of Fig. 6 on theapparatus of Fig. 6; and

Fig. 8 is a further modification of our invention in which a separatechamber including a pressure pickup is used.

Referring now to the drawing and particularly to Fig. 1, numeral 11designates a well bore penetrating a permeable earth formation 12.Sheathing the well bore is a filter cake 13 which is formed in thepermeable sections of the well during the drilling operations bycirculation of drilling mud in the well bore, as is well known. Arrangedin the well bore 11 is a body member 14 which is suspended from theearths surface by a conductor cable 15. Body member 14 has arrangedtherein a pressure chamber or vessel 16 adapted to contain a fluidoxidizing agent of the type previously mentioned. The body member 14 isprovided with a plurality of extension arms 18 which are biasedoutwardly by biasing means 0r springs 19. Extension arms 18 define witha free end thereof a cutting or knife edge 20, a rst recess 21, and

a second recess 22. Extension arms 18 are also provided with internalpassageways 23 having an outlet in recess 21. The internal passageways23 of arms 18 communicate with conduits 24 which connect by a conduit 25to.

a solenoid valve 26.

Arranged in the recess 22 is a thermocouple 27. Thermocouple 27 may bereplaced by sound indicating means or a pressure indicating means, asmay be desired.

A solenoid valve 26 is connected to bag member 16 by a conduit 28. Asupport plate 29 is provided which forms a support for conduit 28. Thissupport plate is provided with passageways 30 and 31. A rst electricallead 32 passes through passageway 30 and connects solenoid valve 26 witha source of energy at the earths surface, the electrical lead 32 beingcarried to the earths surface through electrical conductor 15.Similarly, thermocouple 27 is connected electrically by electrical lead33 to a temperature or pressure indicating means at the earths surface,not shown, the electrical lead 33 passing through passageway 31 in plate29 and being carried to the earths surface through electrical conductorcable 15.

In the embodiment of Fig. 2, identical numerals will be employed todesignate identical parts as in Fig. l. In this embodiment of ourinvention, body member 14 has a pressure vessel 16 arranged therein. Thebody member 14 is provided with a plurality of depending arms 40, 41,and 42. Depending arms 40 define with a lower end thereof recesses 43 inwhich are arranged thermocouples 44. Depending arms 41 define on a freeend thereof recesses 45 and 46. Arranged in recess 46 is a thermocouple47. The arms 41 are provided with internal passageways 48 which have anoutlet in recesses 45. The depending arms 42 define on a free endthereof a cutting or knife edge 49 and a recess 50 in which is arrangeda thermocouple 51. Each of the arms 40, 41, and 42 is attached to thebody member 14 pivotally at points 52, 53, and 54 and is biasedoutwardly from the body member 14 by biasing means or springs 55, 56,and 57.

The internal passageways 48 are connected by conduits 58 to a conduit 59which connects to a solenoid valve 60 which, in turn, connects byconduit 61 to the bag member 16. Solenoid valve 60 may be energizedthrough electrical leads 60a which are carried to a source of energy atthe earths surface by cable 15.

The thermocouples 44 in recesses 43 are connected by electrical lead 62to a temperature indicating means at the earths surface, and thiselectrical lead is carried thereto by electrical conductor cable 15. Thethermocouples 47 are also connected to a temperature indicating device,which may be the same temperature indicating device to whichthermocouple 44 is connected, by electrical lead 63. Lead 63 is likewiselcarried to the earths surface by electrical conductor cable 15.

The thermocouples 51 are also connected to a temperal ture indicatingdevice at the earths surface, which may be the same temperatureindicating device to which thermocouples 44 and 47 are connected, byelectrical lead 64, which is also carried to the earths surface by electrical conductor cable 15.

The apparatus of Fig. 3 is another embodiment of our invention andconsists of a body member 70 which denes a cavity 71 in which isarranged a pressure vessel 72 adapted to contain a fluid oxidizing agentof the type mentioned before. The body member 70 defines a cylinder 73in which is arranged a piston 74 which is connected to a piston arm 75.Piston arm 75 has an L-shaped passageway 76 which communicates withconduit 77 when the piston 74 is moved to the right to its greatestextent. The conduit 77 connects through solenoid valve 78 which, inturn, connects to bag member 72. The valve 78 is electrically connectedby leads 78a through cable to a source of energy at the earths surface.

The piston arm 75 carries a clevis arrangement 79 which is provided withan axle or pin 80. Mounted within the clevis 79 is a spur-likeattachment 81 which deIlCS 4 a plurality of knife or cutting edges 82.Each of the knife edges 82 has outlets 83 which communicate through thehollow member 81 and through pin 80 with passageway 76. Arranged withinthe clevis 79 is a brush or brushes 84 which serves to clean the knifeedegs 82 on rotation of the member 81.

The cylinder 73 connects by a passageway 85 in the body member to aconduit 86 which connects to a double acting solenoid valve 87. Thepiston cylinder is also connected to valve 87 by conduits 85a and 86a,as shown. Valve 87, in turn, connects by conduit 88 to a deformable bagmember 89 which is adapted to contain a hydraulic fluid, such as oil orthe like. The solenoid valve 87 is connected to a source of electricenergy by electrical lead 90 which is carried to the earths surfacethrough an electrical conductor cable, not shown.

Leading into cylinder 73 is a second passageway 91 which is attached toa conduit 92 which, in turn, connects with a double acting solenoidvalve 93. Solenoid valve 93 connects by conduit 94 with an exhaustreservoir 95 which is adapted to contain exhaust hydraulic fluid fromthe cylinder 73. Valve 93 also connects to cylinder 73 by passageway 91aand conduit 92a. Solenoid valve 93 is connected to a source ofelectrical energy at the earths surface by electrical lead 96, theelectrical lead being carried to the earths surface through anelectrical conductor cable, not shown.

The member 81 is provided with a plurality of thermocouples 97 which arearranged adjacent the free ends thereof of the knife edges 82. Thethermocouples 97 are connected by electrical lead 98 to an electricallead 99 which is carried through body member 70 to a passageway 100 andthence to the earths surface through an electrical conductor cable, notshown.

The vessel 72 in cavity 71 may be a deformable bag on which pressure maybe exerted froma source of pressure contained Within the body member 70,as may be desired, or it may be a pressure vessel under pressure.

In the description of the embodiment of Fig. 3, it will be noted thatthe piston arm 75 with the clevis arrangement 79 and the member 81 arearranged to move to the right in a cavity 102 in the body member 70. Itwill also be noted that the piston 74 is provided with means for urgingit to the left, by introducing hydraulic fluid through conduits 85a and86a, and to retract the mem-ber 81 from contact with formation 12. Sincethis device is adapted for obtaining a continuous log of a well bore, itis usually unnecessary to retract same until the log is completed. It isto be noted that cylinder 73 is provided with an annular stop means 74ato provide space for introduction of hydraulic liuid against the righthand end of piston 74.

Referring to Fig. 4, which is a modification of Fig. 3, the solenoidvalve 78 is arranged in a cavity 120 in the body member 70. The solenoidvalve 78 may be energized through leads 78a and is connected by aconduit 121 to a reservoir 122 in which is arranged an oxidizing agent123. The reservoir 122 is enclosed completely by the body member 70 andis held under pressure. The reservoir 122 is internally lined with aliner 124 which is constructed of a non-corrosive material, such astantalum or other non-corrosive material which is not subject to attackby powerful oxidizing agents. The reservoir 122 has a conduit 125leading thereinto which is connected to a solenoid valve 126 which, inturn, is connected by conduit 127 to a source of pressure, such as anitrogen tank 128 containing nitrogen or other inert gas under highpressure. The solenoid 126 is connected by electrical lead 126a to asource of electrical energy at the by a flexible member such as adiaphragm member 200!) to prevent fouling by mud. Arranged in thechamber 200 is a pressure indicating tube 201 embodying amagnetostriction tube which may suitably be constructed of nickel orpermendur. While the chamber 200 is shown adjacent the piston 74 inpiston cylinder 73, it is to be understood that the chamber 200 may bearranged in any convenient place in the body member 70. Themagnetostriction device 201 is connected electrically by electric leads202 to the earths surface by an electric conductor cable to a suitablesound or pressure indicating device.

The device of Fig. 5 is shown in more detail in Figs. 6 and 7. Thepressure indicating device per se 201 is contained in a brass cylinder203 which is filled with a suitable oil. The magnetostriction tube 204is provided with a toroidal winding 205 and is held in the brasscylinder 203 by a threaded bolt 206. The cylinder 203 is provided on itslower end with expansion bellows 207. At its upper end the toroidalwinding is connected by electrical leads 208 to electrical lead 202which carries an impulse caused by pressure to the earths surface and toa suitable display or pressure recording instrument. Themagnetostriction tube 204 is provided with a laminated core 209 which isshown in more detail in Fig. 7.

The device of Fig. 8 is similar to that of Fig. 5 with the exceptionthat the pressure pickup member 201 is arranged in a chamber separatefrom body member 70. In this embodiment of our invention the pressurepickup chamber 210 is carried by an auxiliary cable or suspending means211 adjacent to the knife edged member 81. In this apparatus of ourinvention the pressure pickup mechanism 201 is identical to thatdescribed in Figs. 5, 6, and 7.

The several embodiments of our invention are operated in the followingmanner: With reference to Fig. l, the body member 14 may be lowered intothe borehole 11 by electrical conductor cable 15, the electricalconductor cable carrying the electrical leads 32 and 33 being connectedto suitable indicating devices. As the device is lowered to the lowestdepth desirable in the well bore 11, the extension arms 18 are thenreleased by operation of a suitable tripping mechanism, not shown, whichcauses the arms 1S to be biased outwardly against the wall of the wellbore, allowing the knife edge 20 to pierce the filter cake 13 andallowing a free end of the extension arm 18 to corne into contact withthe formation 12. Since the oxidizing agent is contained in the pressurevessel under a Vhigh pressure, it is possible by energization of thevalve 26 and opening same to release oxidizing agent through the conduit28 and through conduits 24 into recesses 21 and thence into contact withthe formation 12 to react with any hydrocarbons present therein. Thebody member 14 is raised in the well bore and as it is raised thereaction of the oxidizing agent with hydrocarbons or petroliferoussubstances encountered in the formations traversed by the well boreallows a log of the hydrocarbons to be obtained. This log may be ameasure of the temperature increase caused by reaction of hydrocarbonswith the oxidizing agents, or it may be a log of an elastic wave, suchas a pressure or a sound wave. When the latter effects are employed, thethermocouple 27 may be replaced by suitable pressure indicating or soundrecording means, as shown in Figs. 5, 6, 7 and 8. This device whenexposed to a pressure impulse will by compressibility thereof, evenslight, generate an electric impulse which may be transmitted to theearths surface.

The apparatus of Fig. 2 is operated somewhat similarly to that of Fig.l. In this apparatus, however, as the member 14 is raised in the well11, the cutting edges 49 disrupt the filter cake 13. At the same timethe thermocouples 51 cause a temperature trace to be obtained at thewell head which is the temperature of the formation. As oxidizing agentis introduced into the recess 45, it comes into contact with theformation 12 and causes a reaction with hydrocarbons contained thereinwhich in turn causes a temperature rise which may be recorded bythermocouples 47 or by thermocouples 44 carried by arms 40. Thus, two orthree temperature traces may be obtained, the rst being a temperaturetrace of the temperature of the formation and the second and thirdtemperature traces being the result of the oxidizing reaction caused bycontact of the oxidizing agent with hydrocarbons in the formationstraversed by the body member 14. The thermocouples in recesses 44indicate the formation temperature after the oxidizing reaction has beenallowed to proceed.

In the device of Fig. 3, the deformable bag member 89 is exposed to thedrilling mud pressure in the borehole 11. By energizing solenoid 87through electrical lead 90, hydraulic fluid, such as oil, is introducedby conduits 88, 86, and into piston cylinder 73 which causes the-piston74 to move to the right and extend the member 81 such that the knife orcutting edges 82 pierce the filter cake 13 and contact the formation-12.

By energizing solenoid valve 78 through electrical lead 78-a, oxidizingagent under pressure in vessel 72 is conducted into conduit 77 andthence into L-shaped passageway 76 which terminates in outlets 83. Asthe body member 70 is raised in the well bore 11, the member 81 rotatesand the oxidizing agent is introduced into contact with formation 12. Ifhydrocarbons are present, a reaction immediately ensues which causes atemperature rise or generation of a pressure or sound wave. Assumingthat a temperature rise is effected, by virtue of thermocouples 97 thetemperature effect is carried to the earths surface through leads 98 and99 through electrical conductor cable 15.

The device of Fig. 4 operates similarly to that of Fig. 3 with theexception that after the piston 74 has been moved to the right, solenoidvalves 78 and 126 are open in reverse order to allow pressure to bebuilt up on reservoir 122 and thus cause the oxidizing agent to beintroduced into contact with formation 12.

Thus, in the foregoing embodiments of our invention, it is possible toobtain a continuous trace of the formations traversed by the Well bore11 and a continuous indication of the presence or absence ofhydrocarbons therein.

The nature and objects of the present invention having been completelydescribed and illustrated, what we wish to claim as new and useful andto secure by Letters Patent is: v

1. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore having a reservoir adapted to contain a liuidoxidizing agent, at least one extension arm carried by said body memberfor disrupting a filter cake on a wall of a well bore and for contactingsaid formation; means communicating said extension arm with saidreservoir for introducing oxidizing agent into contact with saidformation; and detection means arranged adjacent said communicationmeans for detecting a reaction effect of said oxidizing agent withpetroliferous substances in said formation.

2. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore; a chamber in said body member adapted tocontain a fluid oxidizing agent; extensible means carried by said bodymember for disrupting a filter cake on a wall of said well bore and forcontacting said formation; means carried by said extensible meanscommunicating with said chamber for introducing oxidizing agent intocontact with said formation; and detection means carried by said bodymember for detecting a reaction effect of said oxidizing agent withpetroliferous substances in said formation.

3. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore; a chamber in said body member adapted tocontain a fluid oxidizing agent; extensible means carried by said bodymember for disrupting a filter cake on a wall of said well bore and forcontacting said formation; means carried by said extensible meanscommunicating with said chamber for introducing oxidizing agent intocontact with said formation; detection means carried by said body memberfor detecting a reaction effect of said oxidizing agent withpetroliferous substances in said formation; and means for transmittingthe effect of said reaction to the earths surface.

4. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member; a chamber in said body memberadapted to contain a fluid oxidizing agent reactable with petroliferoussubstances; extensible means carried by said body member having a freeend defining at least one outlet port and adapted to pierce a filtercake on a wall of said well bore and to contact said formation; aconduit in said body member connecting said chamber with said outlet;and detection means carried by said body member for detecting a reactioneffect of said oxidizing agent with said petroliferous substances insaid formation.

5. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member; means attached to said bodymember for lowering and raising said body member in a well bore; acavity defined by said body member adapted to contain a fluid oxidizingagent reactable with petroliferous substances; extensible means carriedby said body member having a free end defining at least one outlet portand adapted to pierce a filter cake on a wall of said well bore and tocontact said formation; a conduit in said body member connecting saidcavity with said outlet; and detection means carried by said loweringand raising means adjacent the outlet port of said extensible means fordetectlng a reaction effect of said oxidizing agent with saidpetroliferous substances in said formation.

6. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member; a chamber in said body memberadapted to contain a fluid oxidizing agent reactable with petroliferoussubstances; extensible means carried by said body member having a freeend defining at least one outlet port and adapted to pierce a filtercake on a Wall of said well bore and to contact said formation; aconduit in said body member connecting said chamber with said outlet;detection means carried by said body member for detectmg a reactioneffect of said oxidizing agent with said petroliferous substances insaid formation; and means for transmitting the effect of said reactionto the earths surface.

7. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore; a chamber in said body member adapted tocontain a fluid oxidizing agent; at least one extension arm carried bysaid body member for disrupting a filter cake on a wall of a well boreand for contacting said formation; means carried by said extension armcommunicating with said chamber for introducing oxidizing agent intocontact with said formation; and detection means carried by saidextension arm for detecting a reaction effect of said oxidizingagentwith petroliferous substances in said formation.

8. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation pene trated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore; a chamber in said body member adapted tocontain a liuid oxidizing agent; extensible means carried by said bodymember defining with a free end thereof a knife edge for disrupting afilter cake on a wall of said well bore and for contacting saidformation; means carried by said extensible means communicating withsaid chamber for introducing oxidizing agent into contact with saidformation; and detection means carried by said extensible means on afree end thereof for detecting a reaction effect of said oxidizing agentwith petroliferous substances in said formation.

9. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore; a chamber in said body member adapted tocontain a fluid oxidizing agent; extensible means carried by said bodymember defining with a free end thereof a knife edge for disrupting afilter cake on a wall of said well bore and for contacting saidformation; means carried by said extensible means for introducing saidoxidizing agent into contact with said formation comprising a conduitcommunicating with said chamber; and detection means carried by saidbody member for detecting a reaction effect of said oxidizing agent withpetroliferous substances in said formation.

l0. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore defining a reservoir adapted to contain a fluidoxidizing agent; at least one extension arm carried by said body memberprovided with a conduit communicating with said reservoir; a knife edgeon a free end of said arm defining at least one outlet port for saidconduit, and detection means carried by said body member for detecting areaction effect of said oxidizing agent with petroliferous substances insaid formation.

11. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore defining a reservoir adapted to contain a fluidoxidizing agent; at least one extension arm carried by said body memberprovided with a conduit communicating with said reservoir; a knife edgeon a free end of said arm defining at least one outlet port for saidconduit, and a thermocouple carried by said arm on said free end fordetecting a temperature increase caused by reaction of said oxidizingagent with petroliferous substances in said formation.

l2. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore defining a reservoir adapted to contain a fluidoxidizing agent; at least one extension arm carried by said body memberprovided with a conduit communicating with said reservoir; a knife edgeon a free end of said arm defining at least one outlet port for saidconduit, and a pressure indicating means carried by said body member fordetecting a pressure impulse caused by reaction of said oxidizing agentwith petroliferous substances in said formation.

13. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said Well bore defining a reservoir adapted to contain a fluidoxidizing agent; at least one extension arm carried by said body memberprovided with a conduit communicating with said reservoir; a knife edgeon a free end of said arm defining at least one outlet port for saidconduit, and

a sound indicating means carried by said body member for detecting asound wave caused by reaction of said oxidizing agent with petroliferoussubstances in said formation.

14. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore defining a reservoir adapted to contain a uidoxidizing agent; at least one extension arm carried by said body memberprovided with a conduit communicating with said reservoir; a knife edgeon a free end of said arm defining at least one outlet port for saidconduit; means for extending said arm from said body member; anddetection means carried by said body member for detecting a reactioneifect of said oxidizing agent with petroliferous substances in saidformation.

15. Well logging apparatus for detecting the presence of petroliferoussubstances in an earth formation penetrated by a well bore whichcomprises, in combination, a body member adapted to be lowered andraised in said well bore; a deformable bag member arranged in a closedcavity dened by said body member adapted to contain a fluid oxidizingagent; at least one extension arm carried by said body member providedwith a conduit communi cating with said bag member; a knife edge on afree end of said arm dening at least one outlet port for said conduit;biasing means for extending said arm from said body member; anddetection means carried by said arm on said free end for detecting areaction effect of said oxidizing agent with petroliferous substances insaid formation.

References Cited inthe file of this patent UNITED STATES PATENTS2,303,727 Douglas Dec. 1, 1942 2,314,753 Asimon Mar. 23, 1943 2,500,125Huber Mar. 7, 1950

9. WELL LOGGING APPARATUS FOR DETECTING THE PRESENCE OF PETROLIFEROUSSUBSTANCES IN AN EARTH FORMATION PENETRATED BY A WELL BORE WHICHCOMPRISES, IN COMBINATION, A BODY MEMBER ADAPTED TO BE LOWERED ANDRAISED IN SAID WELL BORE; A CHAMBER IN SAID BODY MEMBER ADAPTED TOCONTAIN A FLUID OXIDIZING AGENT; EXTENSIVE MEANS CARRIED BY SAID BODYMEMBER DEFINING WITH A FREE END THEREOF A KNIFE EDGE FOR DISRUPTING AFILTER CAKE ON A WALL OF SAID WELL BORE AND FOR CONTACTING SAIDFORMATION; MEANS CARRIED BY SAID EXTENSIBLE MEANS FOR INTRODUCING SAIDOXIDIZING AGENT INTO CONTACT WITH SAID FORMATION COMPRISING A CONDUITCOMMUNICATING WITH SAID CHAMBER; AND DETECTION MEANS CARRIED BY SAIDBODY MEMBER FOR DETECTING A REACTION EFFECT OF SAID OXIDIZING AGENT WITHPETROLIFEROUS SUBSTANCES IN SAID FORMATION.